Forster was charged with first-degree attempted murder Wednesday in Whitman County Superior Court. He is accused of attempting to kill his wife by placing a cardboard box over her head to concentrate nitrogen gas around her face.

Forster obtained a pressurized tank of nitrogen gas by using his status as a graduate student at WSU, according to court documents filed in Whitman County Superior Court. Tanks of nitrogen gas are stored in a supply room at WSU’s chemistry lab but require students, faculty and others to check out supplies through a sign-in sheet, WSU spokeswoman Kathy Barnard said.

Cheryl Forster told Deputy Randy Zehm that her husband placed a box over her head while she slept at their Uniontown home on March 27. She woke up around 3 a.m. and saw a clear tube attached to the box with a regulator.

Jacob Forster, however, explained to investigators that he was considering suicide by asphyxiation in a way that would look like cardiac arrest.

“If you breathe in nitrogen, it will reduce the oxygen level in the blood and there will be nothing for the coroner to find other than the heart stopped,” Forster told Zehm. He had a $500,000 life insurance policy on himself with an exception for suicide.

A nitrogen gas overdose is not detectable in a toxicology report because about 78 percent of air is composed of nitrogen, said a King County medical examiner. The only indicator of such an overdose is in the circumstances.

Forster told Zehm he put the box over his wife’s head to give her just enough gas so that she would not wake up while he killed himself using the same apparatus. He reportedly held the box over his wife for 30 seconds before she woke up, court documents show.

“When she woke up, she thought the box was just sitting on her head,” court documents said. “She said she felt it and then had a sense of panic. She did try to push it off of her, but she could not move it.”

Jacob Forster quickly took the box and tank outside to their home’s shop, she told Zehm. He later said he had been contemplating suicide because he had been diagnosed with depression and school was not going well, according to court records. Whitman County prosecutors believe the story is a ruse.

Jacob Forster planned to attend an expensive California dentistry school in the fall, he told Zehm. His wife said it would likely cost nearly $300,000 to attend.

Last year, Forster persuaded his wife to pursue life insurance policies. Forster’s policy was approved the day before the alleged poisoning; his wife’s policy was approved in February. He told Zehm he would be lying if he said he didn’t think of her insurance policy while he put the box over her, court documents show.

Deputies began recording Cheryl Forster’s phone conversations with her husband April 29. Cheryl Forster later called Zehm and said her husband admitted to the attempted poisoning when she called him. Deputies reviewed the recording, in which Forster told his wife he thought if he told himself a lie often enough he would believe it, court documents show. Jacob Forster is still a WSU student working toward a doctorate in chemistry, Barnard said. An arrest doesn’t warrant immediate expulsion, but if there’s evidence a student broke a rule of conduct it might, she added.